[3835] in linux-net channel archive
2.0.x TCP problem?
daemon@ATHENA.MIT.EDU (Marek Michalkiewicz)
Wed Jul 24 12:02:20 1996
From: Marek Michalkiewicz <marekm@i17linuxb.ists.pwr.wroc.pl>
To: linux-net@vger.rutgers.edu
Date: Tue, 23 Jul 1996 20:46:13 +0200 (MET DST)
Hi,
I just noticed something which I think could be a problem with
TCP in either 2.0.x or 1.2.13. When I telnet from a machine
running 2.0.8 (same problem with 2.0.0) to a machine running
1.2.13, everything is fine until I try to cat a large file.
At this point the telnet session freezes for about a minute.
The problem is reproducible every time I try it. It happens
with telnet, but not with ssh (which works just fine) and not
when transferring large files using ftp.
Below is a tcpdump trace log, A = 2.0.8, B = 1.2.13, started
after logging in from A to B via telnet. Now I do this on B:
cat /usr/src/linux/README
and it freezes before displaying anything from the file.
A and B are a few hops away from each other, on a fast link.
I don't know much about TCP yet, but I hope the log will be
useful for you experts to track down the problem. Feel free
to ask if you need more information.
Even if it's a 1.2.13 bug, a workaround in 2.x would be nice,
just as we have workarounds for old *BSD bugs :).
Regards,
Marek
20:23:05.666111 A.1038 > B.telnet: P 2681480523:2681480525(2) ack 484051729 win 15360 (DF)
20:23:05.666111 B.telnet > A.1038: . ack 2 win 14333
20:23:05.666111 B.telnet > A.1038: P 1:3(2) ack 2 win 14335
20:23:05.686112 A.1038 > B.telnet: . ack 3 win 15360
20:23:05.756112 B.telnet > A.1038: P 3:983(980) ack 2 win 14335 (frag 10234:1000@0+)
20:23:05.796113 B.telnet > A.1038: P 1026:2006(980) ack 2 win 14335 (frag 10235:1000@0+)
20:23:05.796113 A.1038 > B.telnet: . ack 3 win 15360
20:23:05.806113 B.telnet > A.1038: P 2462:3442(980) ack 2 win 14335 (frag 10236:1000@0+)
20:23:05.806113 A.1038 > B.telnet: . ack 3 win 15360
20:23:05.846114 B.telnet > A.1038: P 3898:4878(980) ack 2 win 14335 (frag 10237:1000@0+)
20:23:05.846114 A.1038 > B.telnet: . ack 3 win 15360
20:23:05.856114 B.telnet > A.1038: P 5334:6314(980) ack 2 win 14335 (frag 10238:1000@0+)
20:23:05.856114 A.1038 > B.telnet: . ack 3 win 15360
20:23:05.876114 B.telnet > A.1038: P 6770:7750(980) ack 2 win 14335 (frag 10239:1000@0+)
20:23:05.876114 A.1038 > B.telnet: . ack 3 win 15360
20:23:05.906114 B.telnet > A.1038: P 8206:9186(980) ack 2 win 14335 (frag 10240:1000@0+)
20:23:05.906114 A.1038 > B.telnet: . ack 3 win 15360
20:23:06.106117 A.1038 > B.telnet: . ack 3 win 15360
20:23:06.106117 B.telnet > A.1038: P 3:983(980) ack 2 win 14335 (frag 10241:1000@0+)
20:23:06.516122 B.telnet > A.1038: P 3:983(980) ack 2 win 14335 (frag 10242:1000@0+)
20:23:07.326132 B.telnet > A.1038: P 3:983(980) ack 2 win 14335 (frag 10243:1000@0+)
20:23:08.936153 B.telnet > A.1038: P 3:983(980) ack 2 win 14335 (frag 10244:1000@0+)
20:23:12.146193 B.telnet > A.1038: P 3:983(980) ack 2 win 14335 (frag 10245:1000@0+)
20:23:18.556275 B.telnet > A.1038: P 3:983(980) ack 2 win 14335 (frag 10247:1000@0+)
20:23:31.366437 B.telnet > A.1038: P 3:983(980) ack 2 win 14335 (frag 10252:1000@0+)
20:23:56.986761 B.telnet > A.1038: P 3:1026(1023) ack 2 win 14335
20:23:57.006761 A.1038 > B.telnet: . ack 9642 win 11264
20:23:57.006761 B.telnet > A.1038: P 9642:10063(421) ack 2 win 14335
20:23:57.026762 A.1038 > B.telnet: . ack 10063 win 12288
